1. Field of the Invention
The present invention relates to an apparatus for wire tension control and disconnection detection for a wire-cut electric discharge machine.
2. Description of the Related Art
In a conventional wire-cut electric discharge machine, tension is applied to a running wire electrode (hereinafter referred to as the wire) by subjecting the wire to a braking force by means of a brake gear. The braking force is open-loop-controlled to adjust the wire tension to a predetermined value, and flexure of the wire caused by disconnection is detected by means of a limit switch opposed to the wire, thereby effecting disconnection detection.
According to the electric discharge machine with the construction described above, the braking force is controlled in an open-loop manner, so that the wire tension control sometimes cannot be accurately performed. Since a wire tension control system and a disconnection detection system are arranged independent of each other, moreover, high cost is entailed.